Here are some Generally Accepted CB Radio Frequencies
Usually from 26.000 up to channel 35 is AM operation. Channel 35 and above are for SSB use up to 28mhz (where the next ham band starts).
Buzzing and ticking noises below ch 1 and above ch 40 are usually over the horizon radar from anywhere in the world. These signals usually come in before the DX starts because they are running several thousand watts. These signals are easily spotted if your radio has a waterfall, and you can tell there is a band is opening. There are other noises that can be heard above channel 40 that can be digital modes like SSTV, OLIVIA, ROS, PSK, OPERA, WSPR, PACKET and more…
26.715 AM – Mexican competition channel. Many of these gentlemen are in the United States and Puerto Rico as well as Mexico, and most of them speak english. If they are not in the middle of a key down, they will talk to you. If you go down there and yell at them to speak english, they will not be as friendly.
26.915 AM – DX channel
27.025 AM (Channel 6) – Competition channel (minimum 200 watt carrier on a bird meter, not a dozy meter, and no corny echos or roger beeps)
27.185 AM (Channel 19) – Trucker channel. Corny echo and roger beeps are accepted and encouraged here.
27.285 AM (Channel 28) DX Channel Corny echo and roger beeps are accepted and encouraged here.
27.365 LSB (Channel 36) Popular ssb net channel around the United States. (People on SSB don’t use corny roger beeps and echos)
27.385 LSB (Channel 38) Sideband DX Channel
27.425 LSB (Channel 42) Sideband DX Channel
27.515 LSB (Channel 51) Sideband DX Channel